CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (3,976)	$ (4,209)
Adjustments to reconcile net loss to net cash used in operating activities:
Allowance for doubtful accounts and other	(26)	(69)
Provision for excess and obsolete inventories	43	160
Non-cash lease expense	136	113
Depreciation and amortization	256	246
Stock-based compensation	638	823
Amortization of premium on investments	7	32
Changes in assets and liabilities:
Accounts receivable	235	(885)
Inventories	(168)	252
Prepaid expenses and other assets	(247)	(315)
Accounts payable	(37)	44
Accrued expenses and other liabilities	(1,872)	(813)
Net cash used in operating activities	(5,011)	(4,621)
Cash flows from investing activities:
Maturities of short-term investments	1,500	4,133
Purchases of property and equipment	(106)	(39)
Net cash provided by investing activities	1,394	4,094
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock plans	179	783
Net cash provided by financing activities	179	783
Net increase (decrease) in cash and cash equivalents	(3,438)	256
Cash and cash equivalents at beginning of the period	36,971	44,234
Cash and cash equivalents at end of the period	33,533	44,490
Non-cash investing and financing activities:
Purchases of property and equipment through accounts payable and accruals		314
Operating lease right-of-use assets exchanged for lease obligations	376
Supplemental cash flow information:
Net cash paid for income taxes	$ 30	$ 38